As part of a 15-year project to develop less invasive methods to diagnose pneumocystis pneumonia and to predict responses to therapy, oral washes, induced sputum, and bronchoalveolar lavage are being collected from patients with immunosuppressive dis-eases and respiratory syndromes. Samples for control patients are being collected as well. First, a polymerase chain reaction technique using a unique major surface glycoprotein primer is being used in conjunction with a published primer to develop a method adaptable to clinical laboratories that is highly specific and sensitive. It is hoped that oral wash can replace sputum as the sample of choice. Second, mutations associated with drug resistance are being assessed in all organisms identified to determine the epidemiology and clinical importance of such mutations. Third, markers of strain variation are being assessed to elu-cidate pathogen epidemiology. Collaboration with two other institutions have been initiated to augment specimen acquisition. Initial studies show this approach to be highly sensitive and specific. - Human Subjects